Novel elastomeric products obtained from prepolymer compositions



United States Patent 3,362,921 NOVEL ELASTOMERIC PRODUCTS OBTAINED FROMPREPOLYMER COMPOSITIONS Arthur Ehrlich, Brooklyn, N.Y., and Temple C.Patton, Westfield, and Malcolm Kent Smith, Mountainside, NJ assignors toThe Baker Castor Oil Company, Bayonne, N.J., a corporation of New JerseyNo Drawing. Continuation of abandoned application Ser. No. 443,637, Mar.29, 1965. This application Apr. 8, 1965', Ser. No. 446,719

15 Claims. (Cl. 260-18) ABSTRACT OF THE DISCLOSURE This application is acontinuation of our copending application Ser. No. 443,637, filed Mar.29, 1965, for Novel Elastomeric Products Obtained From 'PrepolymerCompositions, now abandoned, and a continuation-in-part of our copendingapplication Ser. No. 442,507, filed Mar. 24, 1965, for Castor 'Oil,Diisocyanate and Hydroxy Aliphatic Acid Prepolymers and ElastomericProducts Prepared Therefrom.

This invention relates to novel cured elastomeric products, especiallythose which are obtained from prepolymer compositions. Moreparticularly, this invention relates to new and useful elastomericproducts prepared by the reaction of esters of polyhydric alcoholscontaining at least four hydroxy groups and an aliphatic acid of atleast 12 carbon atoms and one or more epoxy and/or hydroxy groups permolecule, with the prepolymer compositions.

In our said copending application there are disclosed and claimed novelprepolymer compositions and cured elastomeric products obtainedtherefrom by reaction with conventional prior art curing agents. It hasnow been discovered that when those novel prepolymers, as well as priorart prepolymer compositions, are cured with esters of polyhydricalcohols containing at least four hydroxy groups and an aliphatic acidof at least 12 carbon atoms and one or more hydroxy and/or epoxy groups,elastomeric products are obtained which exhibit superior electrical andphysical properties in comparison to prepolymer compositions cured withthe heretofore known curing agents.

The reaction of diisocyanates with polyfunctional compounds containingactive-hydrogen groups to produce prepolymer compositions is known. Theprepolymers prepared from an active-hydrogen containing material areobtained by the reaction of a diisocyanate with activehydrogencontaining materials including polyesters, castor oil, polyester amides,and polyalkylene ether glycols as well as mixtures of two or more ofthese classes of polyfunctional compounds. These known prepolymercompositions may be further reacted with conventional curing agents suchas dihydric alcohols, castor oil, glycol esters of hydroxy carboxylicacids, polyalkylene glycols, etc. When these prior art prepolymers arefurther reacted with these conventional curing agents, elastomericproducts are obtained having low tensile strength and elonga- "Ice is tobe used as an adhesive, coating or encapsulant, since on continuedhandling it tends to break, flake off or be pulled away from thesubstrate. Another disadvantage frequently present in the heretoforeutilized prepolymers is excessive shrinking upon being cured.

In the casting resin field there is a need for materials with lowshrinkage, low water or moisture absorption, aging stability, heatstability and good electrical properties, such as low dissipation andvolume resistivity, for use in potting and encapsulating electricalcomponents.

Therefore, one aspect of the present invention is to provide curedelastomeric products having good electrical properties as determined bythe dielectric constant and dissipation factor, good physical propertiessuch as low shrinkage upon curing, low water absorption, agingstability, heat stability, tensile strength and elongation. All of theseproperties make the products of the present invention highly useful asfloccing adhesives, paper coatings, potting compositions andencapsulation compounds for electronic parts.

Another aspect of this invention is to provide a novel class of curingagents which significantly improve the electrical and physicalproperties of prepolymer compositions.

The foregoing aspects of this invention as well as others will beapparent as the description proceeds.

The preferred prepolymer compositions used in the present invention forproducing the cured products are disclosed and claimed in our saidcopending application. However, cured products having good electricaland physical properties are also obtained when prepolymer compositionsdisclosed in the prior art are used. These prepolymers are prepared byreacting an active-hydrogen containing polymeric material withinparticular molecular weight and acid number ranges with a controlledamount of a diisocyanate, with the diisocyanate being present in greaterthan stoichiometric amounts. Examples of activehydrogen containingpolymeric materials which may be used are polyesters, castor oil,polyester amides and polyalkylene ether glycols. Prepolymer compositionsprepared by reacting a diisocyanate with active-hydrogen containingmaterials as fully disclosed in United States Patents Nos. 2,625,531,2,625,532, 2,625,535, 2,692,873, and 2,702,797 are useful in the presentinvention.

According to this invention, it has been found that esters of polyhydricalcohols containing at least four hydroxy groups and an aliphatic acidof at least 12 carbon atoms and one or more hydroxy and/or epoxy groupsper molecule, are useful in curing prepolymer compositions, wherein theresulting product has physical and electrical properties superior to theprepolymer compositions cured with conventional curing agents. The useof the curing agents of this invention for reaction with prepolymercompositions has not heretofore been suggested by the art. The hydroxyand/or epoxy aliphatic acids of at least 12 carbon atoms that form anester, when reacted with polyhydric alcohols of at least four hydroxygroups, may be saturated or unsaturated. Illustrative of this class ofhydroxy acids are the following: ricinoleic acid, 12-hydroxy stearicacid, hydroxy palmitic acid, hydroxy pentadecanoic acid, hydroxymyristic acid, and hydroxy cerotic acid, as well as epoxy derivatives ofthese acids. The length of the carbon chain of the hydroxy and/ or epoxyaliphatic acids is only limited to the extent that commerciaily thereare available aliphatic acids having about 22 carbon atoms. However,hydroxy aliphatic acids hav ing more than 22 carbon atoms are alsocontemplated.

tion, which is a serious disadvantage when the product Among thepolyhydric alcohols, containing at least four hydroxy groups, that maybe reacted with hydroxy and/or epoxy aliphatic acids to form an ester,are the following: .pentaerythritol, erythritol, arabitol, mannitol,sorbitol, sucrose and cellulose.

The esters which are useful as curing agents for the prepolymers areprepared according to known procedures, such as direct esterificationresulting from reaction of a hydroxy and/or epoxy aliphatic acid with apolyhydric alcohol containing at least four hydroxy groups. Other wellknown processes for producing esters can also be employed. The preferredcuring agent for the prepolymers is pentaerythritol monoricinoleate.Other esters which can be used include pentaerythritol 12-hydroxystearate, sorbitol monoricinoleate, erythritol monoricinoleate,cellulose hydroxy stearate, as well as any other esters which wouldresult from the reaction of the above enumerated polyhydric alcohols andaliphatic acids.

Also contemplated are diesters, triesters and tetraesters such aspentaerythritol diricinoleate, pentaerythritol triricinoleate,pentaerythritol tetraricinoleate, etc.

The preferred prepolymers, which are reacted with a curing agent areobtained from the reaction of castor oil, a glycol or a polyglycolmonoester of a hydroxy carboxylic acid of at least 12 carbon atoms andan organic diisocyanate, as disclosed in our copending applicationreferred to herein.

The glycol and polyglycol monoesters of hydroxy carboxylic acids of atleast 12 carbon atoms are prepared by reacting a hydroxy carboxylic acidof at least 12 carbon atoms with dihydric lower aliphatic alcohols orether alcohols, such as ethylene glycol, propylene glycol, hexyleneglycol, diethylene glycol, dipropylene glycol, hexamethylene glycol, andpolyethylene and polypropylene glycols, according to procedures wellknown in the prior art such as direct esterification. These hydroxymonocarboxylic acids may be saturated or unsaturated. Illustrative ofthis class of hydroxy acids are the following: ricinoleic acid,12-hydroxy stearic acid, hydroxy palmitic acid, hydroxy pentadecanoicacid, hydroxy myristic acid, hydroxy cerotic acid, etc.

The preferred esters used in the preparation of these prepolymersdisclosed in our copending application are propylene glycolmonoricinoleate, ethylene glycol monoricinoleate, and propylene glycol12-hydroxy stearate. Also other esters are useful in the preparation ofthe prepolymers including diethylene glycol monoricinoleate,polyethylene glycol monoricinoleate, dipropylene glycol monoricinoleate,polypropylene glycol 12-hydroxy stearate, propylene glycol hydroxypalmitate, etc.

The organic diisocyanates used in the preparation of the prepolymercompositions are those which are known in the art to be useful in thepreparation of such compositions by reaction with active-hydrogencontaining materials. Arylene diisocyanates as represented by thediisocyanates of the benzene and naphthalene series or mixtures of thesecompounds are preferred. Illustrative of arylene diisocyanates that maybe employed are the following: tolylene diisocyanate (2,4/2,6), toluene2,4 diisocyanate, toluene 2,6 diisocyanate, m-phenylene diisocyanate,xenylene 4,4'-diisocyanate, naphthalene 1,5-diisocyanate,3,3'-bitolylene 4,4-diisocyanate, diphenylene methane 4,4'-diisocyanate,1chlorophenylene 2,4-diisocyanate, dianisidine diisocyanate anddiphenylene ether 4,4'-diisocyanate. Other arylene diisocyanates whichare useful include lower alkyl substituted derivatives, halogensubstituted derivatives and also alkoxy substituted derivatives. Otheraromatic hydrocarbon diisocyanates as well as aliphatic polyisocyanatesmay be used but the latter are not as reactive as aromaticdiisocyanates.

The castor oil that may be used to prepare the prepolymers can berepresented by any commercial grade of castor oil. Also useful aremixtures of castor oil and partially epoxidized castor oil. Thepreferred grade of castor oil is a low acid, low volatile gradeavailable commercially as a DB castor oil obtained from The Baker CastorOil Company.

The preferred prepolymers, which are more fully disclosed in ourcopending application, can, for example, be prepared by combining DBcastor oil, propylene glycol monoricinoleate and an arylenediisocyanate. This mixture should be heated for one hour at 50 C.However, other temperatures from about 20 C. to 100 C. may besatisfactorily employed. It has been found that if the mixture is heatedat temperatures as high as 130 C. and above, the viscosity of theprepolymer is so high that it cannot be handled readily.

The propylene glycol monoricinoleate can be represented by any suchcommercial product as Flexricin 9 available from The Baker Castor OilCompany. It has been found that better products are obtained if thecommercial product is treated to reduce the soap content to below .1%and dried to below .1% volatility, and if the product used has a hydroxyvalue of 2901-3. Products with a wider range of hydroxyl value, say290120, and also higher soap and moisture content can be used, but thepreparation is considerably more difiicult to handle.

A further highly advantageous result obtained from combining propyleneglycol monoricinoleate and castor oil is the marked reduction ofso-called bubbling when the elastomers of this invention are cast. Thereaction product of commercial propylene glycol monoricinoleate andtolylene diisocyanate bubbles badly when cured with compounds containingactive-hydrogen groups because of the carbon dioxide obtained in thereaction product. However, when the propylene glycol monoricinoleate iscombined with castor oil, this so-called bubbling is reduced, and bylimiting the presence of soap and moisture normally found in commercialpropylene glycol monoricinoleate to below .l% respectively, furtherreduction in bubbling is accomplished.

The esters of the hydroxy carboxylic acids of at least 12 carbon atomsare used in a weight proportion with castor oil of about to 40% of theester to about 20 to 60% castor oil, the preferred proportion beingabout 61 to 63% of the ester to about 39 to 37% castor oil.

It has also been found that about 2 to 3 NCO equivalents of the organicdiisocyanate per equivalent of hydroxy group in the mixture of castoroil and the ester provide a useful range of prepolymer compositions.

The ingredients used to prepare this class of prepolymers may be simplymixed together in any order. In practice, it is preferred that thecastor oil be mixed with the ester of the hydroxy carboxylic acid, i.e.,prior to reaction with the organic diisocyanate.

The reaction product of castor oil, an ester of a hydroxy carboxylicacid of at least 12 carbon atoms and an arylene diisocyanate results ina prepolymer which is a thick syrupy liquid. The prepolymer obtained isreacted with the curing agent, which is an ester of a polyhydric alcoholof at least four hydroxy groups and an aliphatic acid of at least 12carbon atoms and one or more hydroxy and/or epoxy groups per molecule.

Other prepolymer compositions, as disclosed in the prior art, which maybe used in the present invention, are obtained by the reaction of anorganic diisocyanate with active-hydrogen containing materials such aspolyesters, castor oils, polyester amides and polyalkylene etherglycols. These prepolymers can be prepared according to well-knownprocedures described in the art, and in particular in accordance withUnited States Patents Nos. 2,625,531 and 2,625,532.

The polyesters reacted with the organic diisocyanatecan be prepared bythe reaction of two bifunctional reactants, one being a dibasiccarboxylic acid and the other a glycol. The polyester amides of thepresent invention can be prepared by the reaction of a di-basiccarboxylic acid with diamines or amino alcohols. The polyesterspreferably have a hydroxy number from about 40 to about and an acidnumber from 0 to 7.

Illustrative of the dibasic carboxylic acids, preferably those whosecarboxyl groups are attached to terminal carbons that may be used in thepreparation of the polyesters and polyester amides, include succinic,glutaric, adipic, pimelic, maleic, malonic, fumaric, terephthalic,

citric, etc. Among the glycols which may be used in the formation of thepolyesters are ethylene glycol, propylene glycol, 1,3-tolylene glycol,triethylene glycol, butylene glycol, hexamethylene glycol, decamethyeneglycol, and glycerine monoethers. Among the diamines which are useful inthe formation of the polyester amides are those which contain at leastone primary amino group, including as representative examples, ethylenediamine, propylene diamine, tetramethylene diamine, m-phenylene diamineand 3,3'-diaminodipropyl ether. Primary amino alcohols useful in theformation of polyamides include 3- aminopropanol, 6-a-minohexanol,4-aminobutano1, etc.

Polyalkylene ether glycols, which are useful in the preparation of theprepolymers by reaction with an organic diisocyanate, can be representedby the formula HO(RO) H in which R stands for an alkylene radical such amethylene ethylene, propylene, etc. and n is an integer greater than 1.These polyalkylene ether glycols have molecular weights of at least 750.The preparation of these polyalkylene ether glycols and their reactionwith organic diisocyanates, to produce prepolymer compositions, can becarried out according to United States Patents 2,702,797 and 2,692,873.Satisfactory prepolymers can be obtained by reacting from about 2 to 12moles of diisocyanate per mole of polyalkylene ether glycol.

The preparation of the curing agents useful in the present invention isexemplified by the preparation of pentaerythritol monoricinoleate.

EXAMPLE 1 100 pounds of ricinoleic acid (available as P- from The BakerCastor Oil Company) is charged into a reactor and strong agitationstarted. 38.9 pounds of monopentaerythritol (available under the tradename Monopentek from Heyden Chemical) is added. The reactor is closedand a'water-cooled take-off condenser attached. The re action mixture isheated to 225 C. for three hours, the water formed being removedconstantly. After the threehour reaction period, vacuum is applied tothe reactor. The mixture is allowed to react at 225 C. under vacuumuntil an acid number of 5 or lower is reached. The reaction mixture isthen cooled to 110 C. and filtered to remove unreactedmonopentaerythritol. The filtered product is illustrative of thepentaerythritol monoricinoleate EXAMPLE 2 Charge 2630 pounds of tolylenediisocyanate (2,4/2,6 of 80/20 proportion by Weight) of the high or lowacid type (acidity of 0.010 to 0.015% preferred) to the reactor. Preparea blend of 1035 pounds of DB castor oil and 1615 pounds of propyleneglycol monoricinoleate. Approximately 880 pounds of the blend of castoroilpropylene glycol monoricinoleate is added in 20 minutes and allowedto react. By resorting to cooling, the temperature of the reaction massis allowed to rise only to 35 C. If it goes higher, discontinue reactionuntil it drops to 35 C. before continuing the addition. Add another 880pounds of the blend in 20 minutes. The maximum temperature now should beabout 43 C. If higher, wait until it subsides to 43 C. Add the balanceof the blend in about 20 minutes. Allow the temperature to rise and shutoff cooling at 45 C. However, do not allow the temperature to rise toabove C. If necessary, cool or heat the material to 50 C. and maintainthat temperature for 1 /2 hours. Discharge and package the prepolymer.

This prepolymer will have the following approximate properties:Viscosity (Fenske) 127 stokes, specific gravity at 25 C.=1.11l, percentNCO=14.4:4, color (Gardner) =4.

6 EXAMPLE 3 Following the procedure of Example 2, a prepolymer wasprepared based on:

Parts by wt. Ethylene glycol monoricinoleate 62.0 DB castor oil 38.0Tolylene diisocyanate 90.4

This prepolymer composition has the following approximate properties:Viscosity (Fenske)=390 stokes, specific gravity at 25 C.=1.108, percentNCO 13.7:1, color=light amber.

- EXAMPLE 4 To a mixture of 305.0 grams of castor oil and 53 grams ofepoxidized castor oil (hydroxyl value 225) was gradually added withagitation 242 grams of 2,4/2,6 (:20 proportion by weight) toluenediisocyanate. Equivalents of diisocyanate per equivalent hydroxy groupwere 2.5 to 1. After the exotherm had subsided, the reaction mixture washeated to C. for one hour. After cooling to room temperature theprepolymer had a viscosity of 330 poises.

EXAMPLE 5 Following the procedure of Example 2, a prepolymer Wasprepared based on:

Parts by wt. DB castor oil 62 Tolylene diisocyanate (80/20 type) 38 Tothe prepolymer composition there is added, as a curing agent,pent-aerythritol monoricinoleate or other ester of a polyhydric alcoholof at least four hydroxy groups and an aliphatic acid of at least 12carbon atoms and one or more hydroxy and/ or epoxy groups, to obtain anelastomeric product. The curing process may be carried out at roomtemperature or at elevated temperature (e.g. 50 C. to C.).

If it is desired to carry out the reaction at room temperature, it isexpedient to add a catalyst to speed up the reaction. Suitable catalystsare various organic amines such as dimethylaminoethanol,triethylenediamine, triethylamine, tetramethyl butane diamine, or tinsalts such as stannous octoate or dibutyl tin dilaurate.

The following is an outline of the procedure that may be used for aroom-temperature cure and a heat cure.

Procedure for room temperature cure A suitable catalyst is added to thecuring agent. The catalyst and curing agent are mixed in the correctproportions with the prepolymer until completely homogeneous. Themixture is then degassed from one to three minutes at 5 to 10 mm.mercury pressure. The degassed mixture is then poured into molds andcured at room temperature.

Procedure for heat cure The prepolymer and curing agent are first placedseparately in a vacuum oven and degassed at 50 to 60 C. for 10 to 30minutes at 5 mm. mercury pressure or at least until the foam, whichinitially appears, collapses. At the end of the degassing period, thevacuum is broken and the correct amount of the curing agent is added tothe prepolymer to etfect the cure. After thoroughly mixing the reactantsuntil homogeneous, the prepolymer curing agent mixture is re-evacuatedat 60 C. for two to three minutes at 5 mm. mercury pressure to removeair introduced during the mixing. The degassed mixture is then pouredinto molds and cured for four hours at about 100 C. The curing can alsobe initially commenced at a lower temperature such as 80 C. for thefirst two hours and the temperature is then raised to about 100 C. forthe next two hours. The curing rate can be accelerated easily byincreasing the temperature.

The amount of curing agent added to the prepolymer composition should besufiicient to react with the free Parts of curing agent for 100 parts ofprepolymer:

1,335 X percent NCO (isocyanate) of prepolymer hydroxy value-f-acidnumber of curing agent It is frequently useful to add a non-reactiveingredient to the elastomeric product as part of the final step tochange the physical properties, reduce cost and/or plasticize theelastomer. The following materials have been found to be useful for thispurpose 'but should not be considered as a complete list of suchcompounds: chlorinated biphenyls and polyphenyls, hydroxylated rosin,dioctyl phthalate, acetylated glyceride of 12 hydroxystearic acid,diisooctyl phthalate and fillers such as calcium carbonate and silica.

In Examples 6-7 below, illustrating the heat cured elastomeric productsof the present invention, the curing was carried out as follows. Theprepolymer and pentaerythritol monoricinoleate are placed separately ina vacuum oven and degassed at 60 C. for 30 minutes at mm. mercurypressure. At the end of this period the vacuum is broken and the statedamount of pentaerythritol monoricinoleate, as set forth in each example,is added to the prepolymer to elfect the cure. After thoroughly mixingthe reactants until homogeneous, the mixture is reevacuated at 60 C. forthree minutes at 5 mm. mercury pressure to remove air introduced duringthe mixing. The degassed mixture is then poured into open molds andcured for 2 hours at about 80 C. and is then cured for an additional twohours at about 100 C.

EXAMPLE 6 Parts by wt. Prepolymer Example 2 100.0 Pentaerythritolmonoricinoleate 59.2 NCO/OH ratio 1/1 EXAMPLE 7 Parts by wt. PrepolymerExample 5 100.0 Pentaerythritol monoricinoleate 42.7 NCO/OH ratio 1/1 InExamples 8 and 9 below, illustrative of room temperature curedelastomeric products of the present invention, the curing was carriedout as follows. Triethylenediamine, which is a solid catalyst, isdissolved in the ture is then mixed with the prepolymer in the correctproportions until homogeneous. The mixture is degassed for three minutesat 10 mm. mercury pressure. The degassed mixture is then poured intoopen molds and cured at room temperature. The cured product waspermitted to age at room temperature for at least 7 days.

EXAMPLE 8 Parts by wt. Prepolymer Example 2 100.0 Pentaerythritolmonoricinoleate 58.0 Chlorinated biphenyls (Aroclor 1254) 36.3

Triethylene diamine 0.054

NCO/OH ratio 1/1 EXAMPLE 9 Parts by wt. Prepolymer Example 5 100.0Penaerythritol monoricinoleate 42.1 Chlorinated biphenyls (Aroclor 1254)26.4 Triethylene diamine 0.04 NCO/ OH ratio 1/1 The curing agents of thepresent invention can also be used to cure other commercially availableprepolymer compositions such as Adiprene L (polytetramethylene etherglycol/diisocyanate prepolymer) available from E. I. du Pont as well asother prepolymers disclosed herein.

The following control elastomeric products were prepared. The productswere heat-cured, in the manner described above, with conventional curingagents, the curing agent being indicated in each example.

EXAMPLE 10 Parts by wt. Prepolymer Example 5 100.0 Propylene glyrolmonoricinoleate 48.7 NCO/OH ratio 1/1 EXAMPLE 11 Parts by wt. PrepolymerExample 2 100.0 DB castor oil 119.0 NCO/0H ratio 1/1 EXAMPLE 12 Parts bywt. Prepolymer Example 5 100.0 DB castor oil 86.6 NCO/OH ratio 1/1 Testswere conducted on Examples 6 through 12 to determine the markedlyimproved tensile strength, good electrical properties as determined bythe dielectric constant, dissipation factor and volume resistivity, andother physical properties of the elastomeric products of this invention.The physical properties of these examples were obtained from Aa-inchslabs, aged for at least seven days curing agent, pentaerythritolmonoricinoleate. This mixat room temperature.

TABLE Example Phy si ical Prgrgerties:

ensi e rength p.s.i 3, 860 2 170 2 015 1 330 Elongation, PGI'OhlliL e0 i3? Shore A Hardness 100 97 83 73 45 54 55 Mgisturet gg borligignhpercent, 10

aysa 0 H 4.0 1.8 Electrical Properties: 0 7 2 0 2' 4 2' 6 1 6Diellegntric Constant, 25 0.:

eye es 3.51 3. 66 3. 82 4. 68 6. 41 5. 53 1 kc 3. 33 3. 11 3. 53 3. 643. 83 4. 23 lgokfi. g6 31 3. 29 3. 22 3. 35 4 04 12 DissligttionlFactor, 25 (3.; I 3 O8 on O0 34 cyc es 0. 016 0. 030 0. 027 0. 043 0.108 0. 154 0. 045 0. 011 0. 019 0. 021 0. 034 0. 076 0. 183 0. 074 0.007 0. 012 0. 016 0. 024 0. 036 0. 109 0. 042 0. 005 0. 009 0. 012 O.018 0. 018 0. 044 0. 0E8 1 36X10 1. 86x10" 1. 56 (10 1 03x10" 2. 0X10 5.28x10 6. 42x10 The results in the above table illustrate the highlyimproved tensile strength which is imparted by the use of the curingagents of the present invention. Examples 6 through 9 all showed atensile strength ranging from about 1300 to about 3900, these examplesall being elastorneric products cured with entaerythritolmonoricinoleate. n the other hand, Examples through 12 showed a tensilestrength of between about 200 and 300, these elastorneric products beingcured with standard curing agents. Furthermore, there was also asignificant improvement in the Shore A hardness. Also, the elastornericproducts still retained good resistance to moisture. In addition, theelectrical properties as determined by the dissipation factor,dielectric constant and volume resistivity of the elastomeric productsof the present invention are at least as good as, and in most casessignificantly superior to, the electrical properties exhibited by thecontrol elastorneric products of Examples 10 through 12.

The elastorneric products of this invention are particularly useful forelectronic potting and encapsulating electronic components. Theelastorneric product of Example 9 is particularly suitable for pottingunderseas sonar equipment. The elastorneric products are also useful incoating systems.

While the examples cited herein are exemplary of the invention, it is tobe understood that other modifications are within the skill of the art.The scope of the invention is defined by reference to the claims.

What is claimed is:

1. A non-foamed elastorneric product consisting essentially of the curedreaction product of: (1) the product of the reaction of (a) a polyesterprepared from bifunctional ingredients including at least one dibasiccarboxylic acid and at least one bifunctional reactant in which thefunctional groups are hydroxy groups, said polyester having a hydroxylnumber from 40-100 and an acid number from 0-7, and (b) an arylenediisocyanate, and (2) a curing agent consisting essentially of an esterof a polyhydric alcohol of at least four hydroxy groups and a hydroxyand/ or epoxy aliphatic acid of at least 12 carbon atoms.

2. A non-foamed elastorneric product according to claim 1 wherein thecuring agent is pentaerythritol monoricinoleate.

3. A non-foamed elastorneric product consisting essentially of the curedreaction product of (1) the product of the reaction of a polyalkyleneether glycol having a molecular weight of at least about 750 and anarylene diisocyanate wherein the arylene diisocyanate is used in anamount ranging from about 2 moles to 12 moles per mole of polyalkyleneether glycol and (2) a curing agent consisting essentially of an esterof a polyhydric alcohol containing at least four hydroxy groups and ahydroxy and/ or epoxy aliphatic acid of at least 12 carbon atoms.

4. A non-foamed elastorneric product according to claim 3 wherein thepolyalkylene ether glycol is polytetramethylene glycol.

5. A non-foamed elastorneric product according to claim 3 wherein thecuring agent is pentaerythritol monoricinoleate.

6. A non-foamed elastorneric product consisting essentially of the curedreaction product of (1) the product of the reaction of castor oil, analkyl glycol ester of a hydroxy carboxylic acid of at'least 12 carbonatoms and an arylene diisocyanate which comprises reacting from about 2to about 3 NCO equivalents of the diisocyanate per equivalent of hydroxygroup in the mixture of castor oil and ester, wherein the ester andcastor oil are used in a weight proportion of about 80% to 40% of theester to about to 60% castor oil, said reaction of castor oil, ester anddiisocyanate being carried out at a temperature from about 20 C. to 100C., and (2) a curing agent consisting essentially of an ester of apolyhydric alcohol containing at least four hydroxy groups and a 10hydroxy and/or epoxy aliphatic acid of at least 12 carbon atoms.

7. A non-foamed elastorneric product according to claim 6 wherein thepolyhydric alcohol of at least four hydroxy groups is selected from theclass consisting of pentaerythritol, erythritol, arabitol, mannitol,sorbitol, sucrose and cellulose and the aliphatic acid, reacted with thepolyhydric alcohol to form the ester, is selected from the classconsisting of ricinolcic acid, 12-hydroxystearic acid, hydroxy palmiticacid, hydroxy pentadecanoic acid, hydroxy myristic acid, and hydroxycerotic acid.

8. A non-foamed elastorneric product according to claim 6 wherein theester of (1) is the lower alkyl glycol ester of ricinolcic acid.

9. A non-foamed elastorneric product according to claim 6 wherein theester of (1) is propylene glycol monoricinoleate.

10. A non-foamed elastorneric product according to claim 6 wherein theester is ethylene glycol monoricinoleate.

11. A non-foamed elastorneric product according to claim 6 wherein thecuring agent is pentaerythritol monoricinoleate.

12. A non-foamed elastorneric product according to claim 7 wherein saidester and castor oil are used in a weight proportion of about 61% toabout 63% of the ester to about 39% to about 37% castor oil.

13. A non-foamed elastorneric product according to claim 8 wherein thecuring agent is pentaerythritol monoric-inoleate.

14. A non-foamed elastomeric product consisting essentially of the curedreaction product of (1) about parts by weight of the product of thereaction of castor oil, propylene glycol monoricinoleate, and tolylenediisocyanate which comprises reacting from about 2 to about 3 NCOequivalents of the diisocyanate per equivalent of hydroxy group in themixture of castor oil and ester, wherein said ester and castor oil areused in a weight proportion of about 61% to 63% of the ester to 39% to37% castor oil, said reaction of castor oil, ester and diisocyanatebeing carried out at a temperature of about 50 C., and (2) a curingagent consisting essentially of about 59.2 parts by weight ofpentaerythritol monoricinoleate.

15. A non-foamed elastorneric product consisting essentially of thecured reaction product of (1) about 100 parts by Weight of the productof the reaction of castor oil, propylene glycol monoricinoleate, andtolylene diisocyanate which comprises reacting from about 2 to about 3NCO equivalents of the diisocyanate per equivalent of hydroxy group inthe mixture of castor oil and ester, wherein said ester and castor oilare used in a weight proportion of about 61% to 63% of the ester to 39%to 37% castor oil, said reaction of castor oil, ester and diisocyanatebeing carried out at a temperature of about 50 C., (2) a curing agentconsisting essentially of about 58 parts by weight of pentaerythritolmonoricinoleate, (3) about 36.3 parts by weight of chlorinated biphenyl,and (4) a minor amount of triethylene diamine.

References Cited UNITED STATES PATENTS 3,037,947 6/ 1962 Elkin.3,001,958 9/1961 Swarcman. 2,994,674 8/1961 Rudkin et al. 2,772,245 11/1956 Simon et al.

OTHER REFERENCES Polyurethanes Chemistry and Technology; Part II,Saunders et al., Interscience Publishers, N.Y., 1964, pages 340-343,449, 450.

(Other references on following page) OTHER REFERENCES Based Polyols,Lyon et 211., Journal of the American Oil C P 1 1 f U h F Th J I fChemists Society, vol. 38, May 1961, pages 262-266. astor 0 yo s or retane cams, e ourna 0 the American on Chemists Society, Ehrlich at 211.,vol. DONALD CZAJA f Examme 36, April 1959, pages 149 154 5 L. I.BERCOVITZ, Examzizer.

Solvent Blown Rigid Urethane Foams From Castor- C, W, IVY, AssistantExaminer.

